text:
VFR Navigation, rerouting timing corrections due to wind - rule of thumb?

Consider this reroute on a VFR nav trip from Great Malvern to Chipping Norton.
Maintaining 120 TAS.
Track 110 °M
Heading 103 °M (taking 3/4 of Max Drift - MD)
In still air this 30nm section would take 15 minutes.
However, with a 5-10 headwind the groundspeed would be lower than TAS, around 110-115 kts
Is there a good rule-of-thumb, or quick method in the air to estimate the timings and ETA when considering the effect of headwind or tailwind on the timing of a reroute leg?

Do we assume, as per your question, that you've already estimated your groundspeed. Or are you asking how to estimate ETA based only on TAS and wind info? Also, 50NM in still air at 120kts TAS would take 25 minutes not 15.

its 30 miles not 50 (maybe my 3 isnt curly enough)

Ah sorry my bad. I thought it said 50

@ob318, Why do you say that in still air GS would be lower than TAS?

@MichaelHall I think it's just a bad bot of wording. "In still air this 30nm section would take 15 minutes. However [due to the wind] Groundspeed would be lower than TAS, around 110-115 kts"

That makes sense.  @ob318, I get that you are asking about headwind, but without stating the actual winds your question wasn't as clear as it could be.  I made a very minor edit, please make sure you agree.

If you know or have a reference to Ground Speed, estimating reasonably accurate flight timings is straightforward. Whatever your GS, you will cover 1/10th of the distance in 6 minutes. So at 90kts, 9 miles in 6 mins. At 70kts, 7 miles in 6mins and at 120kts, 12 miles in 6 mins etc. If you mark your pen/pencil with 5 & 10nm distance marks measured in the same scale as your map, it’s easy to interpolate say, 7nm (for say 70kts GS) and mark your map with 6minute marks. If needed dissect these markings in half, for 3 minute markers.

Thanks @Rob Wilkinson. 1/10th distance in 6 mins makes sense. I suppose the most challenging part of it is calculating an accurate Groundspeed, w/o GPS or ADC. But even this task isn’t too difficult.

The rules of thumb for time estimates are:

60kts = 1NM per minute
90Kts = 1.5NM per minute
120kts = 2NM per minute

In between is either a) easy enough to interpolate or b) somewhat irrelevant and might make the difference of plus/minus a minute or so for a long leg.
Your leg is what I would say is somewhat long at 30NM but if you were to calculate using 120kts it would be 15 minutes. For the purpose of estimating using interpolation that time for 110Kts ground speed I would add 10% and round up to the minute giving me 17 minutes.
For the purpose of a PPL diversion I would think this would work acceptably. Pulling out my trusty wizz wheel on the ground, 30NM at 110Kts gives 16.4 minutes. I still think estimating 17 in the air would be just fine!


text:
How are military aviators call signs made?
Military aviators always have a call sign that they are referred to as. I would like to know how they are picked? Is it their personality, surname or what?

Are you specifically asking about US Naval aviators?

Canadians are trying to prevent offensive nicknames.

It is a completely random process, the same way civilians might pick a nickname, although perhaps slightly more intentional.

Think of when you were a kid... did you ever get teased about your name?  Well, that same playground name you hated back then becomes your call sign.

Did you ever do something stupid and get called some funny name to remind you of your error?  That too is fodder for a call sign.

Share a last name with a celebrity?  Your call sign might become that persons name. *

Super cool under stress, icewater in your veins, fast like a predator?  Nope.  Only if you are in the movies do you get a cool call sign like "Iceman", "Viper" etc.

While some call signs are cool and really funny, "Goose" is a much better example of the ordinary, pedestrian sort of names that are more common out there.
There's no special process, your peers will choose one for you.  It may change or evolve, or it may just stick.
What you can't do is choose one for yourself.  For a humorous and accurate example of how the process works, watch "The Maid" episode of Seinfeld where George Constanza attempts to get the nickname "T-Bone" but ends up with "Koko".

P.S. Mine was "Monty", after 1970s game show host Monty Hall.  It was assigned by an instructor during advanced training, and I was never interesting enough to earn another one so it just stuck...

It's how I ended up with Timbo. It was a minor character's name in a movie. I entered the room where my fellow student aviators were watching the movie... and I entered right after a funny scene that featured "Timbo." One of my friends pointed at me and said "Timmmmbbboooooo!" And it stuck ever since.

Reminds me of the Big Bang Theory episode in which Howard tried hard to get Rocketman for a nickname, but ended up with Froot Loops

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text:
Why is airspeed different in climbs and descents although the AoA doesn't change?
Here are the background facts:
This excercise has the objective to familiarise the student with the slow flight characteristics.
The steps are:
1)Establish straight and level, 90% RPM, 15 units AoA, hands out trimmed. (No specific airspeed, it just happens to be appr. 110 KIAS)

Add 5% RPM (so i set it at 95%) and establish a climb with 15 units AoA for 500 ft climb. No bank, whatsoever. (Again no specific airspeed, it just happens to be appr. 100-105 KIAS)

Reduce 5% RPM so you fly straight and level at the new altitude (Same parameters as step 1)

Reduce 5 % RPM (so i set it at 85%) and establish a descent with 15 units AoA for return to the initial altitude. No bank whatsoever. (No specific aispeed during the descent, it just happens to be appr. 115-120 KIAS).

My question is simple. Why is the airspeed different? The answer might be simple. I simply can't figure it out.
Hope i clarified it as much as possible.

What kind of airplane is it?  And are the speeds you observe hands off trim speeds having not touched the trim in each case?  On a tractor engine airplane,  thrust and slipstream effects have an impact on both AOA required to support a given weight, and trim speed, going down when you add power and vice versa.

Military jet trainer plane. Trimmed for 15 units straight and level landing configuration, approximately 110 kias. Then when i change the attitude i just maintain those 15 units. It is a steady climb/dive with 15 units. I dont think i had to do anything with p factor slipstream etc.

You should see the same airspeed for the same AOA and non-accelerated flight with a mild climb or descent.
Except with a Buckeye?
The Buckeye has its thrustline low enough so that at different power settings you have different pitch trim settings. Add power to climb and the thrust pitches the nose up. You now have to trim nose down. Nose down trim means less down force on the tail, which means less lift required by the wing, which means a slower speed for the same AOA.
Conversely, pull power off and the nose wants to drop, leading to nose up trim, more down force on the tail, more lift required by the wing, higher IAS for the same AOA.
I frankly never noticed this effect, and never taught it. Wish I could go back and check it out!

i edited the original post trying to clear things up. Thank you for your help.

Ok, are you actually in a real airplane, or a simulator? I’ve got a 1000 hours in Buckeyes, and you should see the same IAS for your cases.

Actual flight. Normally i execute the Slow Floght exercise at FL140, sometimes FL130. The numbers are a fact. I was prompted by the instructor to see the speed when climbing and diving. And explain to him why this happens.

Well then my swag would be that the Buckeye has a thrustline below the CG, so for the same speed but different thrust you have a different trim condition. Adding power leads to nosedown trim, and pulling it does the opposite. This would be an effect particular to the aircraft, not a general property.

You are talking about a Buckeye, correct? Saw your post on another forum.

Yep. T-2C/E. Yes this seems true, but it still is not my case. I don't care about different settings it same airspeed. I am not keen to keep steady airspeed. All i care about is AoA.

I think this explains it. Updated my answer.

Replaced by the T-45 Goshawk, I wonder why.

It was o-l-d. I think the last ones were built in the 60s. But what a fun plane to fly. Simple and sturdy with good handling qualities. You could spin it any way you wanted too. Sorry to see it go.

Which underscores your comment about the thrust line.  Curious about how one could claim same AOA if trim adjustments were made.  The power off case would require more tail down force for same AOA.  So, yes, like you say (this makes the plane "heavier"), higher IAS for same AOA.

Consider three airplanes: a normal airplane, one that is heavier than normal and one that is lighter than normal. All of them are travelling at 15 units AoA. You will agree that the lighter one will be the slowest (it needs to go very slow as not to have a smaller AoA) and the heaviest one will be the fastest (it needs to be very fast in order not to have a greater AoA).
In the above example we vary the weight of the airplane, but ultimately the change is due to wing loading. In your example, you do not vary the weight, but the tailplane force.
For example, if increased thrust causes a pitch-up moment on your particular airframe, the tail will have increased lift, reducing the wing loading. To maintain a high AoA, the speed will have to be reduced.
(Edit: Initially, I blamed the effect on the thrust vector, which takes part of the weight in a climb. However, @MikeY correctly identified that the drag vector does the same in a descent so that does not explain the higher speed in a dive)

I agree that in a steep climb the thrust would carry more weight and so IAS could be lower for the same AOA, but that property should also hold for a dive, where the drag is now carrying some of the weight. The extreme is an non-accelerating almost vertical climb or dive. For both conditions, you'd have to be at a  very low airspeed to see 15 units AOA.

@MikeY You make a good point. I suppose the main factor must then be the tailplane lift. Thanks for the correction.

Little bit of a "eureka" moment realizing the stabilized speeds for climb and dive in this exercise matches the effects of spoilers vs flaps discussed in another question, except the downforce difference is on the tail. Here the trim position of elevator gives more down force in the dive (just like spoilers, makes plane "heavier") resulting in faster speed.  This is because of the reduction of the power from 95 to 85% (the thrust providing nose up force from "underslung" engine) requires more tail down force trim to maintain same AOA.  Climbing, with more power, tail down trim is less.

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text:
What if one of the navigation lights failed to function on a certified aircraft?
What is the implication if one of the navigation lights failed to function, would it affect the airworthiness certificate of the aircraft?

Hmmm, this could be quite complicated.  The ANO (https://www.caa.co.uk/General-aviation/Safety-information/Air-Navigation-Order-2016/) states only that aircraft flying at night must show navigation lights, but I can imagine that hidden in some annex to some other document there is a requirement that if nav lights are fitted they must be operational.  We probably need a CAMO engineer to quote chapter and verse...

Which country or regulations are you asking about?

In the US, you would not be able to fly that particular aircraft at night and/or IFR since IFR flight requires all day and night equipment to be operable according to Title 14 Part 91.205. Only VFR day flight is allowed.
You would need to check your Minimum Equipment List and/or Kinds of Operation Equipment List to see if the manufacturer would allow flight with that particular piece of equipment inoperable. Then, placard the position light switch as inoperable. It would be best to get it fixed ASAP, just in case you or the next pilot to fly that plane has a flight run late.
If you are already in flight when you noticed that the position light failed, you handle it just like any other failure. Land as soon as practicable. To do this in the case of no position light while VFR at night, I would immediately get on flight-following and explain to them the situation. If you are already IFR, simply inform ATC of a position report with a safety of flight change.
I would prefer to land at an airport with an operating control tower with radar. I am lucky in the fact that I have a few nearby. Just be wary that the failed light is just a failure of the light. And, that it is not indicative of greater electrical failures.
Also, make sure your Transponder is operating in either mode C or S. And, make sure both your ADS-b in and out are currently operating as a safety net.

Except that (like any light) if it fails, it's probably going to fail when it's in use.

@jamesqf - If you are already in flight when you noticed that it failed, you handle it just like any other failure. Land as soon as practicable. In the case of no position light, I would immediately get on flight-following and explain to them the situation. I would prefer to land at an airport with an operating control tower with radar. I am lucky in the fact that I have a few nearby. Just be wary that the failed light is just a failure of the light. And, that it is not indicative of greater electrical failures.


text:
What licenses do I need to transmit on AirBand frequencies?
I am not a pilot, but at my company we are trying to figure out what FCC licenses we need to use to talk to our pilot when we are on the ground and they are flying. My research has led me to mixed answers and I am trying to see the proper way to go about this. I am trying to get my amateur radio license. Will this suffice? Can we register as a ground station to use the radios as well? Here is the link for the ground station information: https://www.fcc.gov/wireless/bureau-divisions/mobility-division/aviation-radio-services/ground-stations
Thanks for all the help

What country are you in?  In my jurisdiction you need an air band licence and can then transmit from the air or ground; it’s assumed you know the protocols and won’t use airband for chit-chat

Welcome to the site. From what distance would you be needing to reach your pilot?

@Frog, Max used the Tag faa-regulations which implies USA (although a more appropriate tag may be fcc-regulations).

The license you are looking for is a Restricted Radiotelephone Operator's License. It authorizes you to use a radio on aircraft, as well as ground stations on the air band. Pilots don't need it unless they plan to fly internationally, there's no test and you only have to apply once, so it's not a bad idea to get one anyway.

That covers the operator. You also need a radio station license to cover the base station radio. The radios in aircraft used to require them as well but the requirement was deleted 20+ years ago as being redundant to the FAA registration of the aircraft, as the registration number is the default call sign for the station. If you're operating a ground station, the FCC wants to know where it is.

You are correct, but since he only asked what license was needed to transmit I left out the need for the base station license.

Abd to clarify something else you mentioned...  No, an Amateur Radio license does not replace or supersede a radio operator's license.

It's not free. It's $70

Do you need a base station license to transmit from the base station?  Because if so then including this in your answer would make it complete.  Yes, the singular word “license” was asked about, but c’mon!

@MichaelHall Yes. See here: https://www.fcc.gov/wireless/bureau-divisions/mobility-division/aviation-radio-services/ground-stations

@fjch1997 It was free when i got it, but apparently there is a fee now, but only if you fly internationally in an N-registered aircraft, otherwise you don't need the license. The FCC web site is down for maintenance so I cannot access the application to see the fee.

@MichaelHall & JuanJimenez, let's try not to escalate this. It's OK to edit the answer of another user in such case, they can always role it back if they don't agree. It is also OK to suggest, in a comment, the user should update their answer. Be aware that hints, no matter how clear to one person, may be missed by another,  for example due to in differences personality or cultural background. You both are experienced users, bringing value to our community. Please assume the best in each other's intentions. No need to drag each other down, let's try to be constructive.

@DeltaLima, thanks for deleting the previous comments.  Personally I am happy to offer suggestions for improvement, but would rather answer myself than correct someone else's work.  But that's just me.

@MichaelHall of course, that is a totally acceptable solution too.

You will need two licenses:

For you, you will need a Restricted Radiotelephone Operator's License. It authorizes you to use a radio on aircraft if you fly outside the USA, as well as ground stations on the air band. (Not required as a pilot in the USA)

For the radio itself you will need a Ground Station License per the link you added to your question.


text:
What is the formula to calculate crossover altitude and speeds?
Indicated airspeed, (IAS) will always correspond to a certain Mach number at any altitude.  If a targeted IAS or Mach number is desired for a climb or descent, at some altitude the pilot will crossover from flying with reference to either the IAS or Mach number, depending on whether the aircraft is in a climb or descent.
How do you calculate the altitude where a target IAS and Mach number correlate with one another?

The optimal IAS for climb or descent as well as the optimal Mach number is typically calculated by the FMGC on the A320 based on the entered cost index.
The pressure altitude at which these values correspond to the same TAS can be calculated from the following formulas (see also this answer):
$$ M = \sqrt{5 \left[ \left( \frac{q_c}{P} + 1 \right)^{2/7} - 1 \right]} $$
$$ \text{CAS} = a_0 \sqrt{5 \left[ \left( \frac{q_c}{P_0} + 1 \right)^{2/7} - 1 \right]} $$
with $q_c$ as impact pressure, $ a_0 \approx 340.3 \, \text{m/s} $ as sea level speed of sound and $P_0 \approx 101 \, 325 \, \text{Pa} $ as sea level pressure.
Flying at a fixed CAS implies flying at a fixed impact pressure $q_c$, which can be calculated by resolving the second equation for it:
$$ q_c = P_0 \left( \left[ \frac{1}{5} \left( \frac{\text{CAS}}{a_0} \right)^2 + 1 \right]^{7/2} - 1 \right) $$
To find the altitude where the impact pressure is the same in both formulas, we can solve the first equation for pressure $P$ and plug in our known $q_c$:
$$ P = \frac{q_c}{\left(\frac{1}{5} M^2 + 1\right)^{7/2} - 1} = P_0 \frac{\left( \frac{1}{5} (\text{CAS}/a_0)^2 + 1 \right)^{7/2} - 1}{\left(\frac{1}{5} M^2 + 1\right)^{7/2} - 1} $$
This pressure can then be converted to an altitude, e.g. using the ISA to get pressure altitude. Plotting this for different values of CAS and Mach gives this:

With typical values for the A320 of CAS 290 kt and Mach 0.78, you would get a crossover somewhere at FL309. The crossover is typically shown on a plot like this, where the TAS of both cases is compared:

Glossary:

IAS: Indicated Airspeed
CAS: Calibrated Airspeed (on the A320: equivalent to IAS since CAS is already shown on the PFD)
TAS: True Airspeed
FMGC: Flight Management and Guidance Computer
ISA: International Standard Atmosphere

And… a handy close approximation for calculating P from baro altitude, H (in ft) is:
for H = SL to 36,089 ft:
P = P_SL(1 - 6.87535E-6H)^5.265
and for H = 36,089 to 65,617 ft:
P = P_SL0.22336e^(-4.80634E-5(H - 36,089))*

A side note on the limitations of air data systems... source, position, and other error corrections can be applied to the sensed pressures that are quite good. However, accuracy is never always 100%. A typical aircraft level requirement is to get reported CAS within 1-3 knots of actual. Sometimes these requirements vary by flight condition.


text:
Why might DTK on GPS not match depicted course on approach plate?
I hope this isn't a dumb question, but I haven't flown a whole lot of GPS approaches and today I observed something that I cannot explain:  There was a 2 degree split between the Desired Track (DTK) displayed on the GPS, and the inbound course shown on the approach plate.
If it matters, the approach was the RNAV 16 Y approach at KRNT, and I was using my club airplane's Garmin GTN 650.  The database in the GPS was up to date, and my approach plate in Foreflight was current.  DTK showed 159, and the plate showed 157.
Not a big difference, but they ought to be the same, right?
At first I thought it might be displaying track direct from my present position, but I had early turned the fix a little coming from the west, and was lined up a bit right which would have made the course needed to correct a few degrees less than 157.
And as I made minor course corrections back and forth across the final approach course the DTK never wavered.
Is there a good explanation for this difference that I'm just not aware of?

How old is the approach (i.e. when was the chart last updated)?  Perhaps the local variation has changed enough over time that the mag course to get from the FAF point to the runway is now, rounded to the nearest whole degree, 2 degrees different? From, say, 157.4 degrees (rounded to 157)  to 158.6 (rounds to 159).

@Ralph J, the plate says Aug 17.  I guess that would explain it, but isn't that why they update things?

Here is the final answer handed down directly from the Garmin technical support department. After a conversation with one of their aviation technicians, he told me that the error seems to be in their database. The same discrepancy (a track of 159 instead of 157) appeared whenever he reviewed the KRNT 16 RNAV Y approach from his end. He even rolled back the database to check previous versions and it has been this way for quite awhile. When asked about a possible magdev discrepancy, he said they they acquire all of their deviation data from the same governmental source that the chart makers do. He said that they are releasing a magdev update in the near future that MIGHT fix the problem, but said that it was most likely just entered wrong in their database. He opened a case file to make sure  it is addressed and said that he will notify when it has been taken care of.

You have gone over and above, thank you!!!

Of course! I was very curious to know the answer myself.

I don't think this is the answer. Two years later there is still a 1-2 degree difference between most RNAV approach charts and Garmin's database. See my answer, from the AIM.

This is explained in the FAA AIM 1-1-6.b.5(j):

Impact of Magnetic Variation on PBN Systems

(1) Differences may exist between PBN systems and the charted magnetic courses on ground-based NAVAID instrument flight procedures
(IFP), enroute charts, approach charts, and Standard Instrument
Departure/Standard Terminal Arrival (SID/STAR) charts. These
differences are due to the magnetic variance used to calculate the
magnetic course. Every leg of an instrument procedure is first
computed along a desired ground track with reference to true north. A
magnetic variation correction is then applied to the true course in
order to calculate a magnetic course for publication. The type of
procedure will determine what magnetic variation value is added to the
true course. A ground-based NAVAID IFP applies the facility magnetic
variation of record to the true course to get the charted magnetic
course. Magnetic courses on PBN procedures are calculated two
different ways. SID/STAR procedures use the airport magnetic variation
of record, while IFR enroute charts use magnetic reference bearing.
PBN systems make a correction to true north by adding a magnetic
variation calculated with an algorithm based on aircraft position, or
by adding the magnetic variation coded in their navigational database.
This may result in the PBN system and the procedure designer using a
different magnetic variation, which causes the magnetic course
displayed by the PBN system and the magnetic course charted on the IFP
plate to be different. It is important to understand, however, that
PBN systems, (with the exception of VOR/DME RNAV equipment) navigate
by reference to true north and display magnetic course only for pilot
reference. As such, a properly functioning PBN system, containing a
current and accurate navigational database, should fly the correct
ground track for any loaded instrument procedure, despite differences
in displayed magnetic course that may be attributed to magnetic
variation application. Should significant differences between the
approach chart and the PBN system avionics' application of the
navigation database arise, the published approach chart, supplemented
by NOTAMs, holds precedence.

(2) The course into a waypoint may not always be 180 degrees different from the course leaving the previous waypoint, due to the
PBN system avionics' computation of geodesic paths, distance between
waypoints, and differences in magnetic variation application.
Variations in distances may also occur since PBN system
distance-to-waypoint values are ATDs computed to the next waypoint and
the DME values published on underlying procedures are slant-range
distances measured to the station. This difference increases with
aircraft altitude and proximity to the NAVAID.

With all due respect, this is not the answer.  The difference in this case is NOT between a PBN system and a course to a ground based navaid.  It was an observed difference between the desired GPS track of an approach loaded from a current database of published approach procedures, and that same track depicted on the plate of the published procedure.

The AIM entry is not just discussing ground based navaids: it is also talking about SIDs, STARs and approach charts (see the first sentence), and those may or may not  be based on ground based navigation aids. The key point is that the chart designer and the database might use slightly different variation: "PBN systems make a correction to true north by adding a magnetic variation calculated with an algorithm based on aircraft position, or by adding the magnetic variation coded in their navigational database."

But why would a chart designer use a MagVar different than the database?  (Or vice versa)  That’s the root of my question, and according to Aaron Holmes’ conversation with Garmin it appears to be an error.

That AIM entry suggests it is because there are different ways of calculating the variation, and perhaps Garmin is more accurate. You can see most charted rnav approaches are a few degrees off from the chart today, so it's clearly not a one off error.

@Ralph J was on the right track with the hidden decimals behind the degrees. This should solve the mystery:

You’ve probably noticed that GPS course guidance is often a degree or three different from the courses shown on the chart. The reason is the magnetic variation used by your GPS, the chart designer, and the VOR defining an airway may all be different.
Approach designers calculate to the fraction of a degree. This means a transition route might start at 141.4 and end at 141.2. The whole route appears as 141 on the chart, but those tenths of a degree measured at the actual turning fix might be the difference between a legal 89.9-degree turn, and a forbidden 90.1-degree turn.

The article is entitled A Bit Over Ninety written by Jeff Van West at IFR Magazine.

I think we are getting close, but it has nothing to do with VOR airways.  This is an apples to apples comparison - GPS to GPS.  Two waypoints, roughly 10 miles apart, with a 2 degree split depending on what you reference.  The only real explanation is that the GPS nav system is drawing from a different dataset than the chart creator.  But shouldn’t we expect a level of standardization to prevent this?

Please check my math, but isn’t that around 2095 feet?!

But it doesn't have to involve a VOR airway. That's just one possible source of variation. The magnetic variation between your GPS and the chart designer could still be off.

As far as the math: Going by the 1:60 rule, there would be 1nm between each radial when you were 60nm from the waypoint. Looking at RNAV 16 Y @ KRNT, I see 3.9nm from waypoint LUTSY to BLEIR. Supposedly, the GPS is giving you a vector from one waypoint to the next rather than all the way to the airport, because that's how computers think. 3.9nm is 6.5% the distance of 60nm. 1nm = 6,076 ft. So 394.94 ft separation between radials. 2 radials difference from GPS to chart would be 789.88 ft off.

OK, but where does the GPS get MagVar?  With an INS it is derived by the difference between TH from the inertial, and MH from the flux detector.  Wouldn’t local MagVar come from the loaded GPS database?  And where does the chart designer get local MagVar?  Presumably from a database?  This is the root of my question, why don’t they use a common, standardized source?  I would expect that the FAA would insist on it!

Your math makes sense, would you mind helping me understand where I went wrong?  10.3 NM from LUTSY to TOYOL, I rounded to 10.  There are 6076 feet in a NM, I rounded to 6k.  So, 10 miles is 60,000 rounded, and we are talking about a 2 degree split.  Using trig, I want to solve for the opposite side to determine the lateral displacement of being 2 degrees off over a distance of 10 NM.  Tangent is opposite over adjacent, so TAN 2 degrees = x/60,000.  Isolating X, it equals 60K*TAN2.  This comes out to 2095 and some change.  That is quite different from your result...  Did I make a mistake?

Remember, if you’re going to calculate the linear distance between 2 points on a circumference, it will be an isosceles triangle - one 2 degree angle opposite of base and double 89 degree angles. You could bisect the base along the 1 degree radial and use that as the hypotenuse of your right triangle calculation.

However... that’s not the issue here. The problem is that you are thinking like a pragmatic human, not like a Garmin 650. If you loaded the RNAV approach, your GPS doesn’t aim directly from LUTSY to TOYOL and use the intermediate fixes for vertical descent reference. It vectors you from LUTSY to BLEIR, then BLEIR to ZULAV, then ZULAV to TOYOL. When you hit LUTSY and it said 159, it was calculating DTK to BLEIR, which was 5.9nm away, not 10.3nm. Thus, the margin of error was smaller, approx. 790 ft instead of 2,100 ft.

I understand that there are intermediate fixes, but from what I recall the DTK remained constant.  I could be wrong, my eyes were moving around, but every time I noticed it was 159.  Knowing this, wouldn’t the approach designer put a number down that matches what the aircrew will see?

Regarding the math, I understand that the earth curves, but are you telling me I did NOT make an error in my trig?  Because the curvature of the earth is imperceptible at 10 miles.  Are you saying that if I laid out a right triangle on a perfectly flat plane that was 2deg, 90, and 88, with leg adjacent to the 2 degree angle being 10 miles long, that the leg opposite to the 2 degree angle would be 2095 ft, but that if that same triangle was curved to fit the earth this leg would shrink to 790?  I’m not buying that, unless I grossly misunderstood your point...

It has nothing to do with the curvature of the earth. It has to do with distance between points on radials that are equidistant from a set waypoint. Think of it like this: You are on the 270 radial of a point that is due east and 10 miles away. To find your distance from a point on the 272 that is ALSO 10 miles away, you calculate the base of an isosceles that is opposite the 2 degree angle. However, if you are flying due north and want to know where you will intercept 272, you calculate it as a right triangle.

You're right, though, they should make sure it matches the chart.

All this is academic, however. The piloting shorthand is to estimate the distance between radials as 1/60 the distance to the waypoint. So, 10 miles to the airport is 1/6 of a mile between radials, or about 1000 ft. 2 degrees would be approx. 2000 ft. as you calculated

Thanks for clearing that up.  Your use of the term circumference threw me off.  That plus the different result.  Bottom line when you get away from the math and radial shorthand discussion is that 2 degrees over 10 miles is pretty significant.  And we still don't have an answer why they don't match.


text:
Do airliners have a "switch" or other means of rapidly squawking emergency?
A standard means of informing Air Traffic Control of an emergency situation is to enter the code 7700 into the radar transponder.  However, in a situation where the radios are busy and the crew is fully engaged in dealing with the emergency, manually entering digits in a control head, (especially in turbulent conditions) seems fraught with the potential to make a mistake, or distract from other important tasks.
The aircraft I flew in the Navy had a rotary switch with an "EMER" position that would immediately broadcast a 7700 code when selected.  Do large modern airliners or business jets have a similar feature for convenience?

@757toga, same years I flew the 1970s era Prowler...  I guess the Navy is that much more advanced!  ;)

We used to joke that squawking EMER was part of the Tomcat climb checklist.

@AdityaGuhaRoy, that would make a good answer.

If they don't, they clearly should!

In the 737, it's just the 4 dials (well, 2 sets of concentric knobs).  Since we're basically always talking to ATC, the need to squawk 7700 is quite rare; all the emergencies I've declared have been done over the radio. At that point, they tag your target as being an emergency, and you get all the special handling you need.
If you had a case where you couldn't reach somebody on the radio (or break in to a crowded frequency), then 7700 becomes more important, and of course it's pretty easy to dial in.  But for as rarely as it would be used, I could see a push-button to immediately squawk emergency as creating more false alarms than times it's validly used.  One difference between airline and GA avionics, our transponder is on the center console, roughly in a flat horizontal orientation, so a push-button can be inadvertently activated with a straight-down motion.  In GA with panel avionics, the face of the transponder is vertical, so possibly fewer opportunities for an unintended press.

How many emergencies have you declared?

Yeah, I wouldn’t recommend a push button where it sits now.

@AnonymousPhysicist In the 737, probably a dozen or more, mostly for a medical issue with a passenger. In prior (Air Force) days, probably about that many. I've been pretty fortunate, flying well-maintained airplanes that rarely have serious issues; I know some people get those sorts of numbers in a year or two.

It's been a few years, but in the 9 years or so I developed Comm/Nav/Surv equipment for the air transport market I never saw any quick select buttons. If you wanted a code, you had to dial it in.
I can't imagine that it has changed as Boeing, Airbus, and the airlines really hate to make any change that would require a flight manual update and create a training requirement.
For a short while after 9/11, there was an industry study going on about a secure method to send/lock in the hijack code (the hijackers had turned off the transponders). When it was all done, the answer was to secure the cockpit doors.


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What extra components does a fuel tank have?
For small-to-mid-size aircraft like V-280, and gulfstream aircraft, what component does their fuel tank has when it arrives for assembly? Is it just a metal box with valves? Or it contains heating elements and damage/rupture/pressure change detector?

I don't know anything specific about the V-280, but I know about conventional airplanes. Everything from the Cessna 172 to bizjets (like Gulfstreams) up to Boeing and Airbus airliners all use integral wing fuel tanks.
The structural wing box actually is the fuel tank.
All of the open areas inside the hollow wing box structure become the fuel tank. When the wing box is assembled together sealant is applied in between all the joints to make it water-tight.
There is sealant in between where the front spar is fastened to the upper and lower wing skin surfaces, and the same is true for the rear spar.
The wing is the perfect available empty space to carry fuel in.
The weight of the fuel acting downward opposes the upward aerodynamic load forces on the wing, allowing the wing to be made less strong (and therefore lighter). It is extremely likely that the Bell V-280's wing is the fuel tank. It is the standard location for fuel on aircraft with a wing.
As you'd expect, the wing box is sealed and outfitted with pumps and pipes for fuel delivery.
If you look at a photo of an aluminum Boeing aircraft (not the 787) which shows the upper or lower surface of the wing, in most cases you will see that the structural wing box is a darker color due to the Corro-guard coating. The composite leading and trailing edges (and flight controls) that are attached to the wing box are usually painted a lighter color (though this is a customer option- United Airline's and Singapore Airline's are all the same color).
Here is a link to a YouTube video about the making of the 747-8 that takes you to the timestamp (16:55) where they show this wing box being assembled (the front of the wing is pointing up in the air):

Here is a C-130 wing with a section of the upper surface of the wing cut out for training:

(af.mil) Michael Gayon does a seal repair inside of a fuel tank on the C-130 Hercules wing at Robins Air Force Base, Ga. Robins AFB units combined forces to procure a wing so students of the 373rd Training Squadron's Field Training Detachment could have hands-on training. (U.S. Air Force photo/Sue Sapp)


text:
Is the pressure change due to volcanic activity a concern?
The recent eruption of the Hunga Tonga–Hunga Ha'apai sent a shockwave so massive that it got picked all over the world by weather stations.
This is the pressure detected one in Italy (source), where multiple spikes were detected:

What I'm wondering is, could such a "sudden" pressure change significantly disrupt flying?
I'm both thinking at high altitude (standard pressure), which might start ascent/descent manouvers (what about RVSM?), as well as low altitude (where one might find themselves in the wrong spot for, say, an approach; or violate MSA, etc.).

Interesting graphics show an initial pressure wave moving West to East, followed by the long path no one around the world East to West. WaPo article also shows records moving across FL and also reports of audible blast heard in Alaska!

I will convert to Freedom Units as that is what I am familiar with:
1028 millibars (the top of the spike) is 30.36 inHg.
1025 millibars (the minimum) is 30.27 inHg.
As a rule of thumb, at sea level, one hundredth of an inch of mercury corresponds to about ten feet of pressure altitude. Thus this difference would correspond to a difference of about 90 feet, if a pilot happened to set the altimeter at 2100 (the spike's maximum) and did not reset it by 2130 (the minimum).
This is a very noticeable difference, and would certainly trigger a "pressure rising/falling rapidly" remark on a weather report. But it really wouldn't have any detriment to most aircraft. Separation standards (both between two aircraft and between an aircraft and the ground) are quite conservative, and can handle a discrepancy of 90 feet.
It would be most dangerous for an aircraft on a non-precision approach, as there is no vertical guidance along the approach path and the pilot must instead make sure to not descend lower than a specified altitude at one or more specified points. An altimeter setting higher than it should be will cause the aircraft to be lower than expected ("high to low, look out below"). But again, procedures are designed with a margin of safety—a difference of 90 feet is probably not enough to cause an accident.
In the flight levels there would be no noticeable effect. Pilots and autopilots would silently adjust their altitudes to maintain the same pressure altitude, which would indeed result in a difference to their true altitudes, but because everyone uses the same altimeter setting everyone would change at once and separation would never be compromised.

Here's pressure chart from Washington/Reagan Natcl Airport of the larger, second East to West pressure wave

@Ian: larger but not by much, perhaps 00.12 inHg, corresponding to ~120' difference in pressure altitude peak-to-trough over ~30 minutes. Again, noticeable but not immediately dangerous. Certainly nothing that would "significantly disrupt flying" per OP's question.

Sticking with scientific units ;) the change in hectoPascals between 1025 and 1028 equates to about 15 meters pressure altitude which is on the limit of whether or not it would trigger an auto-pilot adjustment. It would not affect a landing as internally measured pressure altitude is not used on final.

@Paul, thanks for the SI units! I'm curious about your last statement—what reference does the pilot use when on a non-precision approach, such as a GPS or VOR approach, if not the "internally [or externally] measured pressure altitude"? I was under the impression they did use that alone, which of course is the reason non-precision approaches have higher minima.

Per @randomhead's comment, I have noticed a greater difference than this changing altimeter setting from one station to the next.

Have never before heard the expression "Freedom Units"-- is that what they use in the recipe for "Freedom Fries"?

@quietflyer Yes, the normal Freedom Unit for measuring Freedom Fries is nHa (nano heart attacks.) :P The more greasy ones may be measured in micro heart attacks.

@randomhead - Non-precision approaches do not require accurate vertical guidance because they have decision heights where the pilot has to see the runway to continue. Even CAT I and CAT II instrument approaches have a visual requirement on landing and CAT III approaches require a lot more then just ambient air pressure for vertical guidence.


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Effect of gravity vs airmass on a falling object
Let's say you were drifting along in a hot air balloon at a ground speed of 50 knots at an altitude of roughly 10,000' MSL/AGL.  The airmass is uniform, moving at the same speed at all altitudes.  In your hand is a streamlined, very dense object.  Picture a 5 pound chunk of lead shaped like a torpedo.
If you were to drop this object (over an unpopulated area of course!) would it continue to track along the ground at the exact same speed as the airmass/balloon, or would the vertical acceleration due to gravity overcome the horizontal inertia, slowing the groundspeed and causing it to arc towards a trajectory more perpendicular to the ground?
In other words, would the lead impact the ground directly beneath the hot air balloon, or at some point "upwind"?
My gut tells me that it would fall almost straight down immediately, with only some slight sideways drift, but I don't know how to quantify that hunch.
FYI, this question has its origins in the discussion here:  Force Balance From Wind

https://demonstrations.wolfram.com/TrajectoryOfABomb/

Neat little graphic, but irrelevant and false.  I will explain when I have more time.

Draw the force vectors first (and trust them).  A vertical force vector will not act on a horizontal one. Relative to the air mass, there is no horizontal motion anyways.  The groundbased trajectory is based only the horizontal velocity of the balloon (steady state, not accelerating), and the vertically accelerating falling object, producing an increasingly downward (ballistic) path.  If the "balloon" is out of the atmosphere and travelling fast enough, the dropped object will orbit.

@Michael Hall Yep, for a powered plane (luckily for it) the "bomb" will fall behind it.

I felt it was safe to presume a uniform airmass because of the obvious effect, but for posterity I will edit.  Thanks for the answers, turns out my gut was wrong!  And thanks to Ron for the video; by recognizing immediately that it was wrong it helped me to look at this scenario from another angle, and to understand where my misconception originated.  Paradigm adjusted.

P.S.  Another contributor to my way of thinking was the visual image of reeling in a fishing line as it drifted by in a river.  How the force of your reeling would pull hard enough to overcome the current, causing the line to slice through the water.  I failed to realize that at the scale of the earth the “gravity” from the pulling force would not pivot, but would be uniform along the river bank.  In effect it would drift too, pulling from a constant direction.

This answer assumes that the wind is uniform in direction and speed, from the balloon all the way down to the ground.
The object will impact the ground directly below the balloon, not "upwind" of the balloon.
As the falling object accelerates vertically, the trajectory of the falling object as viewed from the ground reference frame continually becomes more and more perpendicular to the ground.  Yet the horizontal components of airspeed, force, and acceleration are all zero throughout the entire fall, so the falling object remains directly under the balloon.
As viewed from the airmass reference frame, the trajectory of the body is purely vertical, i.e. completely perpendicular to the ground, throughout the fall.
The horizontal component of the object's groundspeed is constant throughout the fall, and equal to the wind speed.
Now imagine simultaneously dropping a low-density object and a high-density object from the balloon.  Both would be directly below the balloon at the moment of impact, but they would impact at different times.
For more, see Force Balance from Wind
Also, note that saying the object will tend to fall straight down relative to the earth, rather than relative to the balloon and the airmass, is essentially saying that the earth is a privileged reference frame, which goes against the laws of physics.

I thought you might chime in!  ;)  Looking forward to hearing from some dissenters...

@MichaelHall, the only thing to dispute here is the mention of density as you can have two objects of the same density, but still with very different drag (e.g. a solid rod and a wide open cone). And of course it only applies as long as Earth curvature is negligible over the range, but at scales where it isn't, we would be talking about space reentry and balloons wouldn't be involved.

Newton's first law of motion states:

An object in motion stays in motion with the same speed and in the
  same direction unless acted upon by an unbalanced force.

The instant you let go of the object, it has 50 kt sideways motion, and 0 kt vertical motion.
First, let's assume this happens in a vacuum, so only gravity applies. This is essentially a classic projectile motion problem, where you are firing your object at 50kt from a height of 10,000 feet. The gravity applies perpendicular to the sideways motion, so it has no effect on that initial velocity. The two velocities can be considered separately. Using the equations of motion for the vertical component:
$10000 ft = 0.5 * 32.17405 \frac{ft}{s^2}*t^2$
Solving this for $t$, it takes about 25 seconds to fall from 10,000 feet. To find the final velocity:
$v = 32.17405\frac{ft}{s^2} * 25s$
This gives a speed of 802 ft/s, or 475 kt. In that time, it has continued to move at 50kt along the ground, same as the balloon.
$s = 84\frac{ft}{s}*25s$
This puts the impact point about 2100 feet away from where it was directly above when it was dropped.
But this is assuming there is no drag, and this is Aviation.SE after all. Let's see what the drag might be. Let's assume the drag coefficient for a streamlined object is 0.05 and the reference area is 0.5in2.
$D = 0.05 * .002373 \frac{slug}{ft^3} * 802\frac{ft}{s}^2 * \frac{1ft^2}{2*24^2}$
We end up with 0.066 lbf of drag from the vertical speed at the bottom of the fall. To find how that affects the acceleration of the object:
$a  = \frac{0.066 lbf}{0.155 slug}$
This results in 0.427 ft/s2 which is only 1.3% of the acceleration due to gravity. For such a streamlined object, the drag will have only a small effect of slowing the fall. If we assume the wind is blowing at 50kt with the balloon and is constant with altitude, the object will continue to move with the wind, experiencing no drag in this direction, and will remain directly below the balloon until impact.
You'll notice the drag depends on the shape of the object, and the acceleration from that drag force depends on the mass of the object. Changing either one will have an effect on the trajectory of the object. An object with lower mass or higher drag will be affected more by drag, taking longer to reach the ground. If the object is moving with the wind, there is no drag acting against the lateral motion, so regardless of the time taken to fall, it will remain directly below the balloon.


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Is there a standard traffic pattern altitude for ultralight aircraft?
Many airports publish a Traffic Pattern Altitude.  For those that do not, the standard that pilots are expected to fly is 1000' AGL per the Pilot's Handbook of Aeronautical Knowledge.  (The AIM and CFRs likely cover this as well...)
Are ultralights expected to fly the same pattern altitude, or something different?  If different, what is the standard and where is it published?
EDIT:  This advisory circular references a 500' AGL pattern:  AC90-66A
I may answer my own question later, but leaving open for now...

I think ultralights use a traffic pattern similar to helicopters i.e. opposite direction to fixed wing traffic pattern (default to an RH pattern) and at 500 feet AGL as opposed to 1000 feet.

@CarloFelicione, that would make complete sense, although the AC I just linked above doesn't seem to go into that sort of detail.

According to that circular, and to the best of my understanding, it can vary from airport to airport, depending on the surroundings, nearby airspace, flow of fixed wing traffic, etc. but typically ultralights will have their own takeoff and landing area on the airfield proper separate from the main runways and taxiways used by fixed wing aircraft. This is typically a grass strip running parallel to a runway (ex KDIJ); you don’t exactly need an 10,000 paved runway to fly your Eipper Quicksilver on a sunny Saturday!  Under the Part 101, they are required to remain clear of all other traffic.  Typically the airport will establish a pattern going in the opposite direction, and inside of fixed wing traffic around the airfield, and TPA will be at 500’ AGL for ultralights and rotorcraft.


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What is the difference between VFR and IFR in class G airspace?
What is the difference, and how would an outsider discern, whether a flight was conducted under Visual Flight Rules or Instrument Flight Rules in class G airspace?  (United States, FAA jurisdiction, although I’d be interested in EASA or other answers)
To be clear, I am not asking about receiving an instrument approach clearance to transit and land at an airport within class G airspace, or picking up an IFR clearance before take off and flight into controlled portions of the National Airspace System.  I am talking about flying an entire flight under IFR within uncontrolled airspace, without radar services, and without talking to ATC.
Presume that the aircraft is certified for IFR flight, and the pilot is instrument rated and current.  The do-nothing default would be VFR, so:

What is the actual trigger for enabling the pilot to make the flight under IFR if no clearance is issued?
I.e. what specific action must be taken to be considered operating under IFR, and not VFR?

And here’s the kicker to this scenario… the weather is clear and a million.  That’s right - VMC, not IMC!
Yes, the pilot could make the flight under VFR, and without radar and ATC service there is no compelling reason not to, he/she just wants to prove to Aviation SE readers that it can be done.  You can file and fly IFR under VMC in controlled airspace so you should be able to do the same in class G, right?
Is this what would make the flight IFR then, the filing of an IFR flight plan?  What would be the response of ATC in such a situation if they are not required to issue a clearance, and cannot “control” the flight?

Related - https://aviation.stackexchange.com/q/78751/34686

What is the difference [between a flight] conducted under Visual Flight Rules or Instrument Flight Rules in class G airspace?

The difference is that the VFR flight would be conducted in accordance with Visual Flight Rules, and the IFR flight would be conducted in accordance with Instrument Flight Rules. Some examples:

The VFR pilot would navigate by pilotage, dead reckoning, or use of a non-IFR-certified GNSS display. The IFR pilot would navigate by their instruments (conventional NAVAIDs or an IFR-certified GNSS display).
Should IFR conditions be encountered, the VFR pilot would have to deviate from their planned route in order to remain in VFR conditions. The IFR pilot would be able to continue as planned.
The VFR pilot would comply with VFR fuel reserve planning (14 CFR 91.151). The IFR pilot, having departed in VFR conditions, would similarly be bound by 91.151 but would be prudent to plan fuel in accordance with 91.167 instead—in case they encounter unforecast IFR conditions along their route.
The VFR pilot would cruise at a cardinal-altitude-or-flight-level
plus 500', as required by 91.159, provided they were more than 3000' above ground level. The IFR pilot would cruise at a cardinal-altitude-or-flight-level exactly, as required by 91.179.

I believe that last point is the only way an outside observer would be able to definitively tell which flight was which. Of course there could be other evidence, like the VFR pilot flying circles and loops that would be unlikely for the IFR pilot. But assuming each one simply flew direct via GNSS, altitude would be the observable difference.
One very important similarity is that (when weather conditions permit) 91.113 requires both pilots, VFR or IFR, to see-and-avoid other aircraft. Both types of pilot must, if necessary, alter their course to avoid a collision and to comply with the right-of-way hierarchy.

What is the actual trigger for enabling the pilot to make the flight under IFR if no clearance is issued? I.e. what specific action must be taken to be considered operating under IFR, and not VFR?

The actual trigger, besides the requirement that the pilot and aircraft be legal to fly IFR, would be the pilot performing the necessary IFR flight planning actions. That's all. No clearance is required to operate under IFR in uncontrolled airspace. Even a filing an IFR flight plan, while certainly a useful piece of insurance, is not a requirement unless operating in controlled airspace.
In other words, IFR in uncontrolled airspace is a state of mind.

"IFR in uncontrolled airspace is a state of mind."  This.  I believe that both answers are technically correct, but I cannot tell you how dissatisfying this is...

Well, I would say that you simply conduct the flight under instrument flight rules.  Assuming all of the conditions above were true, and you were conducting a flight under instrument flight rules from untowered departure and destination airports, both in Class G airspace, and along a route completely in Class G airspace, and you can descend and land at your destination in VFR weather minimums ie no instrument approaches, it would be very similar to conducting that flight under VFR.  The only difference is that you would controlling the aircraft by solely reference to instruments (but practicing see-and-avoid if in VMC), and flying a course defined by electronic instruments, most probably RNAV systems using GNSS guidance.  Since you’re flying under instrument flight rules, you could depart in zero-zero weather conditions (under Part 91), but you must be able to descend and land at your destinations airport in visual meteorological conditions (no available instrument approach).  Filing a flight plan, thence opening it with flight service when airborne and making periodic position reports with flight service enroute is highly recommended, but not required under law.
That also assumes that you physically could execute such a flight, as there is very little, if any, class G airspace above 1200 ft AGL left in the continental United States, and it’s rapidly shrinking up in Alaska, too!

you could depart in zero-zero weather conditions I don't think that's right, the NTSB has ruled that taking off in IMC without a clearance can qualify as 'extremely dangerous' and in violation of section 91.13(a). https://www.faa.gov/sites/faa.gov/files/faa_migrate/interps/2016/Lamb_2016_Legal_Interpretation.pdf

The NTSB is not a rulemaking body and there is no law against it. That being said, should a mishap occur on a zero-zero departure, you probably would be cited under §91.13.  The entire proposition described above would easily be considered careless and reckless due to the increased risk involved.  Nevertheless, in certain situations, the FAA will not hold your hand to prevent you from doing stupid and risky things.

@Max, just because the NTSB has found one such situation to be a violation of 91.13 does not mean all other situations would be a violation. In particular, if controlled airspace did not extend down to a very low level (700'/1200' AGL) but rather only extended down to 14500' MSL, there would be much more room to fly IFR/IMC outside of controlled airspace. In particular there would be an opportunity to level off at a safe(r) IFR altitude instead of simply crossing your fingers that you will break out before reaching Class E.

The NTSB does not make rules, but its judges do make rulings. Here's the one I mentioned: https://www.ntsb.gov/legal/alj/OnODocuments/Aviation/3935.pdf @randomhead It cites the risk of collision with other aircraft (no see-and-avoid, no ATC). Given this, could takeoff into IMC in Class G without a clearance ever be in compliance with the §91.13(a) Careless or reckless operation rule?

@Max, one of the central points in the judge's reasoning in that case was that the respondent was reckless because he took off into IMC without an ATC clearance and therefore would not have ATC's help in avoiding known aircraft. But it's very possible for there to be unknown-to-ATC aircraft flying around as well, especially back in 1990 when we didn't have ADS-B receivers dotted all over the landscape. Given this, could takeoff into IMC in Class G with a clearance ever be in compliance with 91.13(a)?


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How can stand numbers 1, 2 and 3 have the coordinates of 07.9 minutes North ins, but stand number 9 have the coordinates of 07.8 minutes North?
How can stand numbers 1, 2 and 3 have the coordinates of 07.9 minutes North ins, but stand number 9 have the coordinates of 07.8 minutes North? As can be seen from the blue line I drew visually, although the stand number coordinates number 9 is further north than the other stand locations (1,2,3), an ins coordinate is assigned to number 9 more south than the others. How is this possible? Is there an error? Or is it a deliberate purpose? The image is taken from the LTBU airport page 10-9A Jeppesen chart.

Mistakes happen, and this is quite obviously an error.
Not unlike your error of including an extra 0 in the original question! - "07.08" ;)
Presumably someone creating the chart was misinformed and simply thought that the number of spots continued by one more in a Southeast direction when they made the table.

Hahaha I wasn't aware of my error. Thanks for the answer!


text:
Zero experience to A320 in seven months?
Some flight schools advertise a "direct path to A320 or B737 f/o after 7 months." Is it a more difficult transition to go to a fly-by-wire aircraft straight out of initial training?  Are there tangible benefits from gaining experience on similar aircraft like the 737, that use conventional steel cables and hydraulically actuated flight controls, before transitioning to fly-by-wire?

I'm voting to close this as opinion based. 'Is it a good idea' is subjective.

To the close voters, please see my recent edit.  It's hard to keep opinion completely out of answers, but sometimes the wording of the question can be geared to encourage a somewhat objective answer.

@757toga, the question does not mention USA anywhere, and basically everywhere else the requirement for SIC at air carrier is just CPL and that only requires 250 hours (+ type rating, but the hours spent doing the type rating count for CPL too).

@JanHudec, in countries other than the USA is it common to be hired into the right seat of a 737 or Airbus after 7 months and 250 hours?

First, I’m very certain that after 7 months of “initial training” (presuming you start at zero hours) that you would NOT be flying a 737 or Airbus.  You should recognize that sometimes marketing materials are intentionally vague.
Yes, it is very possible that after 7 months of training, (under the condition that you prove yourself proficient and obtain Private, Commercial, Instrument, CFI and Multi-engine ratings all within that time frame...) that you may very well enter a "direct path", but there's nothing to say that the direct path won't include a contractual number of years as a CFI at the same school, followed by some other number of years at a regional airline that partners with the school.
Just make sure you understand the specifics of what they are offering, the commitment required, and adjust your expectations accordingly.  If you haven't yet started training you are a LONG ways away from choosing between 737 or Airbus!
However, whenever that transition occurs, the challenges a new pilot faces getting comfortable in new equipment will mostly be related to the physical size, complexity of systems, level of automation, plus company and industry policies and procedures. Whether the flight control surfaces are moving as a result of steel cables or electrons is largely transparent to the pilot while actually flying. Side stick vs yoke may be an issue, but by the time you get there you should have the skills to adapt to either.
Gaining flight experience on larger, increasingly complex aircraft before you upgrade is more important than fly by wire vs conventional.

+1  Also, you need to get the confidence to be the decision maker without an instructor there as a safety net, that requires a decent amount of time flying solo and a lot of flying in unfamiliar situations.

Short answer, no.
I was recently at a Part 141 flight school in Florida 2 years ago. These  are geared to quicker, airline-like class progression than a Part 61 school.
It took from start of December to early April to get Private pilot license. I had 65 hours (minimum is 40 which is quite low IMHO.) Me and another student finished same day, first in a class of 11. Some students finished a few days later, some a month or two, one barely finished in a year.  Mind you some students had full funding, some didn't, which plays a large factor in speed. We all had some weather delays for long flights, etc.
To get Instrument rating next it took me to mid June. I finished with about 85 hours total flight. Instrument weeds out a lot of non-technically minded or lazy studier students. Some more of my class didn't finish this in 1 year.
Then comes Commercial. The material is mostly a rehash of private pilot. Some students finish single-engine in around 130 hours, and figure a couple months. Most international students do multi-engine commercial training, since foreign airlines often/usually hire with just 250 hours for multi (vs the 1500 in USA, which can be reduced). So from there you would go to an airline academy and learn whatever aircraft they have - which may be anything bigger from DHC8 to B737, etc. US students usually do single-engine commercial, then get flight instructor I and II (where you relearn everything from right seat 30-50 hours or so, learn new material, and have difficult check rides), then much later do multi-engine commercial.
A lot depends when you get Commercial if you can find employment. This is a world of research unto itself for jobs and hour/experience requirements.
Me? I decided to do Part 61 single-engine where you need 250 hours. I rented a plane for 100 hours and flew where I wanted in various weather. I learned a lot more as a pilot than the school would allow in their risk-adverse renting rules. But since doing that, I got off track and haven't finished Commercial since. I would like to get back out there but need money and I have the loans to pay.

It is going to be an opinion base answer if I tell you what I think. Fact is you can go from PPL from scratch to pilot a B737 or A320 within 7 months as only PPL, multi engine endorsement, type rating and multi crew endorsement and something I forget are required. No need even a CPL or ATPL to fly these big planes.

 IMHO you need some experience before flying the big jets. Don’t rush it.

Technically correct, but realistically impossible for all but multimillionaires.  Just a hunch, but I don’t think the OP is considering buying an Airbus…


text:
Why do the New York Special Flight Rule (SPFR) and Skyline routes exist simultaneously?
If I understand correctly Skyline just allows you to fly 1300-2000 ft, while SFRA allows you fly surface to 1300 ft.
The question is, why there are 2 airspaces like this? Why can SPFR not cover surface all the way to 2000 ft?


text:
Why is buffet and/or stall more likely to occur in a thunderstorm?
the correct answer for this Q is:
"Because in a thunderstorm the speed of the aeroplane for a given power setting decreases, and the stall speed increases"
I would like to know why in a thunderstorm speed of the airplane decreases and why stall speed increases.
Appreciate all the answers

That sounds like a poorly written exam question and answer. Can you provide the source?

Yes, the answer is poorly worded, but perhaps the others are worse.  If you list the other choices we could perhaps help you understand why you can rule them out.  Sometimes the “least incorrect” is the only option.

That's an atrociously badly written answer... speed and stall speed can vary quite a bit in a thunderstorm, but to say that the one decreases & the other increases, is just wrong.  VTC because we're not here to explain the intent behind somebody's badly written testing materials.

This is a strange question and answer. (It would be great if you could post a link to or citation for this "question" and "answer.")
First of all... don't fly in thunderstorms!
If caught in a thunderstorm, there are some considerations that might shed some light on this "answer," but they're related only in the sense that they happen to use some of the same words and phrases...
Airspeed: while executing the trusty 180-degree-turn (turn around and get out of the storm!), the pilot would want to slow down to reduce aerodynamic stress on the airframe in the heavy turbulence that can be expected in a thunderstorm. But it's the pilot who does does, by reducing power; not the storm.
Stall: thunderstorms tend to feature both turbulence and significant wind shear. Both can cause increased load factor, and stall speed increases at higher load factors (equivalently, the shifting angle of attack may reach the critical angle even if you're above stall speed for level flight). In layman's terms: getting bumped and jolted around a lot can cause a stall.
I don't see that the stated question or answer really grasp these concepts, so I'm not sure this really answers the question. But it's the best I can come up with.

Question is from my ATPL(A) course


text:
What does the suffix "A“ mean on specific PW1100G(A) engines?
Some time ago I tried to find out what the difference between a PW1100G and a PW1100GA exactly is. I am asking this question here because there seems to be no information online that could be useful for me to find this out.

Where do you find references to a PW1100GA? It doesn't seem to exist.

I already have seen it on a a321neo A/C status page when I visited the flight deck (PW1133GA), so it does exist and that is what I meant before, there is nothing about it online…

It probably refers to "Advantage" series, PW1100G-JM Advantage. About 1% more thrust and uses a little less fuel. Certified in 2023 and entered service in 2024.
https://prd-sc102-cdn.rtx.com/-/media/pw/products/commercial-jet-engines/pratt-and-whitney-gtf/family/files/pw_gtf_pc_pw1100g-jm_2021_web.pdf

as you can see on this specs, the ,,advantage“ version of the PW1100G is signed with /2, whereas there are non-advantage models with the suffix ,,A“.


text:
Was heat or thermal equipment used during search and rescue efforts for Uruguayan Air Force Flight 571?
Uruguayan Air Force Flight 571 crashed in the Andes mountains on 13 October 1972. Was thermal or heat imaging equipment utilized for flight 571s search and rescue attempts? Such equipment dates back to as early as 1950.

What was the ambient temperature in the area of S&R efforts?  AFAIK, thermal imaging equipment is not very effective for certain types of S&R when the ambient temperature is above a certain threshold.  This was likely even more true 51 years ago.

How do you know such equipment wasn't used?

Your premise is incorrect, although there were some examples of thermal imaging cameras in the early 70s the technology wasn't very good, it wasn't until the 80s that it improved enough for this type of use case.

Also such technologies were often very expensive and only army could have them (and it requires trained personal). I assume it was not the priority of the South American armies/air forces to get such technology (and if they had, probably it was used on navy)

I think the suggestion that the Uruguayan military had thermal or IR cameras in 1972 is extremely dubious. Without support for that assertion, the question makes no sense.

I edited to remove the unsubstantiated presumption that it was NOT used.  Matt, if you know for certain that wasn't used please feel free to roll back my edit, but we'd like to ask that you provide enough information showing it wasn't to justify the original wording.


text:
What does "in function of traffic" mean?
I’ve been familiarising myself with circuit procedures hoping to increase my knowledge (I’m not a pilot, but have a great interest in aviation). I have come across the following instructions:

When the runway is behind the aircraft and in function of nearby
traffic in the circuit, the pilot must descend to the aerodrome
circuit altitude in function of traffic and can now join the beginning
of the downwind leg.

I have no idea what they mean by "in function of traffic." I have looked everywhere but can not find reference to this term. Can anybody help?
Thanks.

I assume this is from this site?  It appears to have been machine-translated from the Dutch, and has a lot of grammar errors.  The term is not standard English or standard aviation terminology.

Yes, please provide a source for these sort of terminology questions.  Because my first instinct reading it was that it was a poor translation from some other language.  If you are a fluent or native English speaker you should do your learning from reputable publications originally written in English, (FAA, Jeppeson, etc).  If not, study in your native language.

@mins, that's a reasonable interpretation of a bad translation, and could stand as an answer.

Tevildo, that is indeed the site that I found the information on.

According to FAA and ICAO standard phraseology, "in function of traffic" has no meaning, assuming that it was a wrong translation, it seems to be "due Traffic"!

As the question is based on a poor wording, due to the site, the actual meaning can be different, but here is a possible one, for what it's worth:

in function of nearby traffic in the circuit, the pilot must descend to the aerodrome circuit altitude in function of traffic

This sentence seems to say the pilot must join the downwind leg from the crosswind leg, avoiding other traffic (also joining the circuit) during the descent, and traffic already in the circuit (in the downwind leg).

Source.


text:
What are FAA rules regarding FBO operations encouraging food/ refreshments for pilots?
Specifically chapter, section, paragraph relating to food services for private pilots at an FBO.

It is not within the jurisdiction of the FAA to regulate ground-based food service.

Wrong. FAA administers Federal airport funding and has the right to regulate services at airports under the threat of withholding such funding. See e.g. AC 150/5190-7, AC 150/5190-6, Airport Sponsor and Airport User Rights and Responsibilities.

@user71659 Neither Advisory Circulars nor the other document you linked to are regulatory per se, and none of the documents you linked is responsive to the OP's question. Yes, the FAA might withhold funds based on an airport's discriminatory policies toward vendors at the airport, but that isn't what the OP is asking about. I think this answer, given the scope of the question, is correct.

@user71659, I am confident in my answer, but of course I cannot prove a negative.  If you can provide chapter, section, paragraph relating to food services for private pilots at an FBO in an answer of your own I will happily concede, delete my answer, and upvote yours.  I trust Ralph's assessment of the applicability of the links you posted and didn't read them myself, but if there is something specific that you think applies to food service please quote it directly.

AC150/5190-7, says Federally-funded airports must be operated for the benefit of the public, and it is strongly recommended to have a plan and standards for their operation. Specifically refer to 2.1(c)(2)(a) saying plans should be in place for "Access to passenger loading bridges/steps, sanitary rest rooms, boarding hold
rooms, telephones, food and beverage service, and other passenger concessions." This is strictly optional, but if your airport provides poor services, you won't be getting Federal funding.

@user71659, but you need to consider the context: Section 2 is "guidance for developing minimum standards" and contains sample questions for the "airport sponsor" to consider in developing those standards. It does not say that food MUST be provided, nor does it dictate the quality of the food. It is advisory, not regulatory, and you admit it is "strictly optional". Besides, withholding funding is not the same as having the authority to actually regulate something. And finally, the specific subsection you referenced is for passengers, not pilots.

If you disagree then please post your own answer, I am confident in mine.


text:
How would you know the difference between a compressor stall and a surge based on indications in the cockpit?
I understand the difference between a compressor stall and surge.
Stall: One or two blade stages exceed the critical AoA, the airflow is turbulent, and the smooth airflow through the compressor is disrupted
Surge: Occurs after a compressor stall where most or all the blade stages are affected from it, there’s a complete disruption of airflow through the compressor and restricts airflow to the engine.
A stall produces a big bang, flames at the back and sometimes in front of the engine due to flow inversion, and severe vibrations and engine damage in a severe stall. In the cockpit we can see fluctuations in RPM and raise in EGT.
But what noises/indications a pilot from the cockpit would hear/see in a compressor surge? Are they similar?

Stall and surge are two different, although related, physical phenomena.

Stall: One or more blade stages exceed the critical AoA, the airflow is turbulent, and the smooth airflow through the compressor is disrupted

Correct.
After a stall initiates, the airflow is disrupted. In an axial compressor, a stalled stage causes increased AoA on neighbouring blades, which in turn may enter a stall. The original blades may, at this point, exit the stall due to the decreased airflow, hence we have a rotating stall, or the stall can spread to the whole inlet section.
If the stall affects a large part of the compressor stage, the airflow from inlet to outlet cannot be guaranteed, so the (higher) pressure downstream of the stage causes a backflow, and

big bang, flames at the back and sometimes in front of the engine due to flow inversion, and severe vibrations and engine damage

This inversion is called surge.
In the end, it is surge that you experience in the way you describe, and it is a consequence of a severely stalled compressor. For brevity sake, people say "the compressor stalled" instead of "stalled and now entered surge".


text:
How do I get rid of this chord line along the x-axis when importing an airfoil into XFLR5?
Whenever I try to import an airfoil into XFLR5, I always notice the chord centerline along the x-axis as you can see in the picture.
Is there a way to somehow get rid of this line?
I'd be thankful for any type of advice since this line is making my airfoil analysis unusable at the moment.

Indeed, I mean the centreline of the chord. I was able to get rid of this line using Selig airfoil data instead of lednicer airfoil data.
But what causes that Lednicer airfoil data are basically useless for importing an airfoil into XFLR5? Is this phanomena only occurring within XFLR5?

However, when running an airfoil analysis with this ''weird'' centerline that came with the airfoil data the results in XFLR5 are wrong and not usable. Most likely due to xflr5 assuming that all panels are interacting with the free stream in some way.

if you found the answer provided by Rob answered your question, you can click the check mark next to it to mark it as the accepted answer.

You most likely are importing the points with the wrong order.
Usually programs are looking for points to start at the TE and go clockwise along the lower surface to the LE and then back to the TE along the upper surface.
However, if you did lower surface then upper surface, both TE to LE, then there might be a line connecting the lower LE to the upper TE like you see here.


text:
Why don't aircraft use D.C generators?
I need to research DC generators in aviation, but the only information I can find is about AC being converted to DC. This information is not exactly what I’m looking for.
The only information I could find is that DC generators were used in older or vintage aircraft and have been replaced for reasons of optimization and weight. However, this information wasn’t very clear, so I'm wondering if there are any modern aircraft that uses DC?

I talked with a pilot once who replaced his DC generators with alternators.  He said with the DC generators, he would have to run his engine at ~1500 RPM at night to just get a little light and to power one comm and nav radio.  Once he converted to alternators, he could run all his electronics with the engine at idle.  The DC generators don't output a lot of power with the engines at idle but do a decent job with full power.  He said the alternator weighed a bit more but was well worth the compromise.

For an interesting read Santiago, read up on why trains use DC or in some cases AC. Very interesting!

The HondaJet HA-420 and Embraer Phenom 100/300 use DC starter generators - https://www.ametekpds.com/products/power-generation/dc-brush-starter-generator

Short answer
When large mechanical powers are required, AC motors are used, it's not particular to aircraft. The limiting factor of DC motors is the commutator ring. When AC motors are used, AC sources are required.  Note this is 3-phase AC, using three phases (over two or over DC) helps simplifying motors: 3-phase motors have a predetermined direction of rotation; they can start without assistance.
Motors and generators are similar devices used in reverse, in one case a current creates a magnetic flux, in the other case a magnetic flux creates a current. The pros and cons of generators and motors are mostly the same, in particular DC generators also need a commutator ring; They have the same power limitation. So the most effective combination is AC generator and AC motor.
AC generators are usually driven by the engines, which rotation rate changes with thrust demand. For a long time the problem has been to stabilize the frequency of the generator using mechanical systems. However today the frequency is no more a problem, we have efficient inverters to electronically stabilize it, so AC generators are also used for small power needs.
I'm detailing the DC motor limitation below, but for your research you may be interested also in these questions:

What is the typical voltage and frequency of the electrical generator in an airliner?

How much electrical power does one generator produce on a large turbofan?

How does the A350/380 operate on Variable Frequency AC generators?

AC generators are called alternators, DC generators are called dynamos. Dynamos have been replaced by alternators on cars a long time ago. As commented, dynamos don't deliver much current at low speed: We needed to run the engine at a high rpm to actually load the battery on a car with a dynamo. Alternators can load a battery with the engine at idle speed.
Details follow.

Need to invert pole polarity in motors
Motors are based on how two magnetic poles interact: Poles of the same polarity are pushed away, poles of different polarities are attracted.
In a DC motor:

There is a stator, it can be made of permanent magnets or windings. For simplification let's use one permanent magnet with two poles N and S (or two magnets oriented such as the inner poles are respectively N and S)

There is a rotor made of solenoids (windings) within the stator. Let's use a single solenoid. A solenoid fed with DC current behaves like a permanent magnet, creating two magnetic poles N and S. The poles are reverted, becoming S and N, if the direction of the current is reverted.

(Source)

Magnetic attraction is used to rotate the rotor solenoid until its poles are aligned with stator poles of opposite polarities. When the poles are aligned they keep their position due to attraction, the rotor stops rotating.

To unlock the rotor, the polarity of either the rotor or the stator is inverted, this changes the attraction into a repulsive force moving the rotor poles towards the next stator poles, where they are locked again. The polarity is inverted again and the cycle repeats.
Commutator ring
Inversion is done by a ring and two brushes connected to the DC source. The ring rotates with the rotor, it has segments connected to the rotor pole solenoids. The brushes deliver the current to the segments.

(Source)
As the ring rotates, the segments are in contact with each brush alternatively, the solenoid polarity is constantly inverted.
As the power of the motor increases, the current in the ring segments also increases. But the contact surface between the brushes and the ring segments cannot be increased past a limit, the ring temperature increases with power due to impedance. Wear is stronger, maintenance is required more often.
In addition:

The number of poles is usually large in order to smooth the rotation, meaning the number of segments required is large, and their size smaller, further limiting the maximum current.

Sparks are created between brushes and segments. The effects of the sparks increase with current.

Use AC to remove the commutator ring
The other solution is to change the current direction by directly using AC (AC motors have also other advantages). The inverter is not required anymore.
Advantage of AC generators
Larger aircraft uses AC generators which are more simple and more robust. The frequency is 400 Hz instead of 50 Hz for different reasons, it is mostly historical, and linked to the need to have constant speed drives. With the development of efficient current inverters, the need for constant speed has been removed. One advantage is a higher frequency reduces the size of the voltage transformers since the maximum flux the core can transfer is proportional to frequency.
The 400 Hz frequency was selected by US military long ago as a tradeoff between feasibility of constant speed drives given the engine speed ranges at this time and the corresponding weight reduction (generators, transformers, motors, actuators and wiring, as a higher frequency also requires wires with a larger cross-section due to the skin effect).
Most recent aircraft actually generate AC with a variable frequency, depending on the engine speed. This current can be efficiently rectified, and converted back to AC with the desired frequency, e.g. 400 Hz.
Both AC and DC are present on a large aircraft, but the generators are AC (except the batteries of course). Smaller aircraft which don't require large electrical sources may still have DC generators with a more limited power.

If I may add to "a higher frequency reduces the size of the voltage transformers since the maximum flux the core can transfer is proportional to frequency," this is a huge advantage because using a transformer to increase voltage and decrease current means you can use thinner wires to carry the same power.  This means less weight.  DC-DC transformers are much more complicated beasts, especially high power ones.

@CortAmmon: But the most frequent case in an aircraft is to use transformers to decrease the voltage, not to increase it. The transformer is smaller because of the frequency allowing a smaller core for a given power, whatever the voltage.

@CortAmmon Planes are so small, that voltage step-up is not needed. The main power loss, maintenance and reliability issue are the mechanical constant-speed drives. The 787 generates variable-frequency AC in the engines, about 1/3 of the power is consumed as variable-frequency AC, but the largest motor loads, 1/2 the power, draw from a 270 VDC bus; essentially a split-VFD topology. The A380 and A350 utilize a distributed architecture, where all the AC loads get variable-frequency power.

DC generators aren't widely used in general:

the brush of a DC generator isn't very durable, reliable, and it sparks.

most generators have the rotor inside the stator, so the rotor is naturally smaller than the stator. And between the magnets and the coil, the magnets are smaller. As a result, generators in general have rotating magnets and stationary coils. This structure is impossible for a DC generator, but:

it's easy to convert AC to DC with a rectifier.

In other words, even though there are brushless DC motors, they are in fact AC motors with a built-in VVVF (Variable Voltage Variable Frequency) drive. Same to brushless DC generators: they are in fact AC generators with a built-in AC-DC rectifier.

DC generators were useful for many purposes in an era when mechanical commutation was more efficient than any available form of electronic rectification.  Even if one sets aside reliability issues, mechanical commutation is often less efficient than modern electronic rectification.  The only applications where I could see a DC generator as being useful would be those where one would want the polarity of the current to be controlled by motor direction, and even those could probably still be better handled electronically.


text:
Turbofan ‐ turboprop/shaft hybrid?
If a turbofan engine can create more thrust than a standard turbojet engine, would a turboshaft engine benefit from using a turbofan to power the shaft, in a hybrid kind of set up?

I may have found the glitch in my own theory.   Do turbofans have both high/hot and low/cold pressure thrust?!  Or is the thrust only measured by the fan/low/cold side?  If so would that mean the turboshaft would need both high/hot and low/cold pressure sides driving it?  Idk.   Might just be two separate questions now. Lol Sorry guys/gals

Cutting some corners to keep this simple but:
Turbofans make more thrust than turbojets, because they employ a large fan driven by a jet engine. This way it can accelerate a large amount of air, and while the acceleration is less than what a turbojet engine does to the air that passes through it, the efficiency is greater anyway. Accelerating a large amount of air a little is better than accelerating a litte amount of air alot.
Turboshaft engines are basically jet engines that convert pretty much all of the energy of the exhaust jet into rotational movement, which is then routed through a gearbox to drive a propeller, rotor or whatever needs to be driven.
One could say the core engine is the same in all of the three cases here, what varies is how the energy of exhaust jet is used. Turbojet simply relies on the high speed of the exhaust as it is, turbofan uses most of the exhaust energy to drive the fan, and turboshaft uses all of the energy from the exhaust to drive the output axle (and gearbox).
A turboshaft run by a turbofan makes little sense. It's like running a car with an outboard motor.
What you may be thinking about is a geared turbofan. They do exists, this engine employs a gearbox to reduce the rpm of the fan driven by the jet engine. This enables the use of larger fans, as the fan blade tip speed stays lower even though the blades are longer.

Turboshaft produces torque, not trust. It is a turbine with a power shaft or an accessory drive. It uses the torque to produce thrust, but there is a variety of power consumers, for example, a helicopter rotor or a ship propeller.
turbofan is a turbine and a fan. The turbine produces torque and a bit of thrust, the fan produces thrust.
There is also turboprop which is a turbine with a propeller.
Effectively, they are the same core with different power consumers. Plus, turbofan also utilizes the power of hot exhaust gases.
This answer goes into more details on differences between turboprop and turboshaft and how they are used - and more.

Welcome to Av.SE!

I’m not sure what you’re asking here. Keep in mind that a turboshaft engine creates no thrust, only power. A turbofan engine does not necessarily create more thrust than a turbojet, it’s just more efficient at high subsonic and transonic speeds.  Probably a better way to view a turbofan engine (or at least high bypass turbofans) is that it’s a gas turbine-powered ducted fan, operating on the same principles as the ducted fan engines that you find on some radio controlled aircraft.


text:
For a given mileage, which is more profitable, multiple short flights or fewer long flights?
In a simplified scenario, which is more profitable for an airline, operating 10 short flights (400 miles) or 5 long flights (800 miles), for a total of 4,000 miles flown in each case?
To make things simple lets consider both cases will have:

same aircraft
same weather
same payload
same landing fees
same fuel price
same number of passengers
only one class type of tickets
no extra revenue generated during flight
Assume that the long flight is twice the price of the short flight.

You do a lot of assumptions, but you miss the economic scale. If it is not profitable, airlines either do not flight or they increase ticket price. Why to invest on a less profitable route? (Then management, cost reductions, optimisation differentiate airlines, but that is outside your question).

You didn't mention ticket prices.  Because this is the only variable that affects revenue, which after operating costs are subtracted, affects profitability.  And it is the variable mist easily controlled by the airline.  Without including it the question is unanswerable.

Rather than the short/long haul comparison, look at "stage length": How to understand "Stage length, for payload calculations includes 85% wind"?. The stage length influences profitability.

@MichaelHall I left price out intentionally because I thought that would be part of the answer I'm looking for(like how would the airline setup tickets pricing). If you ask me, I would say the long flight would be twice the price of the short flight since is twice the distance???

Asking how airline pricing strategy works is like asking how to design an airplane.

@MichaelHall I have decided to update the question stating long flight is twice the price of the short flight.

Keep in mind that operating short flights (or partnering with an airline who does so) is part of how airlines profitably operate long flights with a hub-and-spoke route network. More people will fly the long-haul flight between Los Angeles and Tokyo if people who live in Las Vegas, Phoenix, etc... can access it through connections provided by short-haul flights between these cities and Los Angeles. The airline is concerned with profitability of their network as a whole beyond just the profitability of each flight.

@ZachLipton yes I'm aware of that, like American-Envoy partnership for example.

OP edited the question and added information. I think the question was closed in haste, not considering the edits OP made.

The latest edit dropped ticket price out of the equation.

@Jpe61 thanks for updating the title and description, it made it more clear of what my question is/was.

The only case when it may make sense (but one would have to run the numbers) is for very long flights, e.g. Europe-Australia, and comparing non-stop vs. a single stop near the mid-point, where, on a direct flight, the amount of fuel to be carried during the first half of the flight for the second half could have an impact on the total cost. On shorter hops as in your example, the difference in fuel is small compared to the overall (you’ll probably need more reserve fuel than actual fuel for the flight).

Also, as you ask which is more profitable, but then impose many conditions which mean the revenue doesn’t change, your actual question here is if the cost changes. Profitability is quite likely to depend a lot on revenue changes: whether the airline would have more or less passengers on the various segments, whether they would be able to charge more (or less) for the same itinerary (because it becomes shorter/more convenient or the opposite), etc. There are then considerations specific to the route and airports and the potential market for each.

Assuming the ticket for the twice as long flight would cost twice as much, it would be more profitable to fly longer flights.
For the same amount of flight distance, 4000 miles in this case, flying shorter trips takes more time due to turn around times, and less time travelling at cruising speed, so you earn less in the same amount of time.
Shorter flights would consume more fuel due to having twice the amount of taxiing and takeoffs (descents will not compensate for takeoff, not even close).
Shorter flights would have twice the landing fees and hightened maintenance cost for the aircraft since number of operations is a deciding factor in some maintenance cycles.
Crew cost would most likely end up being higher since the actual time used for flying will be less in short flight scenario, and many salary models have built in operation compensation.
Shorter flights also require double the support functions (such as dispatch/flight planning etc.)

Those were very good points. Didn't thought about the landing fees were going to be double, duh now thinking about it is obvious, lol. Thanks

In aviation, as in many industries, "longer production runs" are way more efficient and profitable than short stints. Less hassle, more producing.

@Jpe61, more fuel efficient, absolutely.  But profitability depends heavily on pricing strategy and load factors.

@MichaelHall yeah that depends a lot on the pricing, but I just wanted to focus this question in the distance alone in a simple 1 to 1 comparison. Jpe61 brought up the points that answered my question, which now that I see them most were obvious, but as they say sometimes you need someone else to show you what you can't see.

@Jpe61 any idea about how much more profitable would the long flight be? (just a rough estimate). Like 10%, 20%, 30% more?

@MichaelHall I think you missed the OP updated the question to include the pricing strategy: the long flight is twice as expensive as the short one. I tried to address the load factors by giving a crude estimate of the efficiency of time usage, I may reword a little to better describe that: over time, shorter trips will yield less miles, and for that reason (in addition other factors) to  also less profit.

@gabe as I guess you know, your question is pretty much academic. The variables in this game are such that real world pricing simply does not work that way. Raw operating costs have surprisingly little to do with actual ticket prices, but I would guess, and I can't stress enough that this is just a guess with some knowledge behind it, the longer flight has 10 to 20 precent lower opertating cost per mile than the shorter one in the scenario you presented.